Curable silicone compositions are used in photocouplers, light-emitting diodes, solid-state image sensing devices, and other types of optical semiconductor devices having optical semiconductor elements in order to seal the elements. It is demanded of these compositions that cured products thereof do not absorb or scatter light emitted or received by the optical semiconductor elements, and, at times, that the cured products be hemispherical, hemicylindrical, dome-shaped, or a similar convex shape in order to improve the optical properties of the optical semiconductor device.
For example, Japanese Unexamined Patent Application Publication No. 2008-231199 discloses potting a thixotropic curable silicone composition to seal a light-emitting element, and imparting the sealing body with a convex lens shape.
Japanese Unexamined Patent Application Publication No. 2009-235265 discloses depositing a thixotropic curable silicone composition dropwise upon a substrate using a dispenser to seal a light-emitting element, and imparting the sealing body with a convex lens shape.
However, the methods disclosed in Japanese Unexamined Patent Application Publication Nos. 2008-231199 and 2009-235265 present the problem that it is difficult to control thixotropy, making a sealing body having the desired hemispherical, hemicylindrical, dome-shaped or the like convex shape impossible to obtain in practice. In addition, the high viscosity of the thixotropic curable silicone composition impedes swift dispensing thereof from a dispenser, leading to the problems of time being required to dispense the composition and threads forming when the composition is dispensed. Moreover, depending upon the filler added to the curable silicone composition in order to impart thixotropic properties thereto, the curable silicone composition may cloud, leading to problems in optical properties.
The present invention was achieved in light of the problems in the prior art as described above, and has as an object thereof the provision of a method capable of efficiently manufacturing an integrated piece in which a curable silicone composition is used to form a convex cured product upon a substrate.